Method of orienting whipstocks



Aug. 20, 1935. s. H. wlLLlsToN METHOD OF ORIENTING WHIPSTOCKS Filed Sept. 30, 1933 Patented Aug. 20, 1li-)35oI Aberdeen, Wash., Surveying Company, Philaa corporation of Delaware Application September 30,' 1933, Serial No. 691,635

This invention relates to the drilling of wells method ofA and has particular reference 'to a i checking the orientation of a whipstock designed to guide a drill in a deflnitefdirection as is nec- 5 essary, for example, in straightening a crooked Well. As is those produced by rotary drilling, deviate very considerably from the vertical at even moderate distances below the surface, such deviatons being apparently due to lack of uniformity in the soil through which the drill' is passing an being particularly noticeable'in the case of rotary drillin g since the rotation of the drill stem appears to promote the production of a tortuous hole. If a bore hole deviates to a substantial degree from the vertical it may entirely miss the locality which is believed to contain oil.

to properly orient the whipstock and check the orientation to insure that a proper correction of the direction of the bore holewill be made. i

The orientation of a whipstock necessarily involves a knowledge of the path of a bore hole so that a preliminary survey must be-made to ilnd the direction and position of the lower end of the hole.

Various methods of orienting whipstocks are actions of the Institute of Mining and Metallurgy (1911-1912, pages 481 to 4895 Carrying out any ofthe known processes isquite diilcult by reason of the various manipulationsinvolved, so that they are impractical.

In the process described in the above publication, the whipstock is lowered on the end of a drill stem, being secured'to the drill stem by means ofsoft metal rivets which can be sheared ofi to eventually leave the whipstock in position. Where the bore hole does not have an excessively tortuous path, the whipstock may be positioned by drill stem orientation, the corrections for tortuosity being in certain cases negligible in comparisony 60 with the" errors arising in the alignment and orientation of the drill stem sections. Whether or not the effects of tortuosity must be calculated can be determined, or sometimes inferred without calculation, from a consideration of the path of the hole as determined by a preliminary survey.

well known, many wells, particularly.

Once a bore hole begins to deviate from the vertical little c an bedone I known, a typical one being described in the trans-- It is the object of the present invention to provide means to check the position of the set whipstock, this being eiected by including within the length of the drill stem at its lower end a surveying instrument capable of indicating accurate- 5' ly the azimuthal position of the whipstock while the whipstock is being lowered and set. 'I'he whipstock is oriented by the setting oi the drill stem while in the same operation its position is checked by a reliable instrument. The necessity 10 for accuracy even within wide permissible ranges substantially requires that the well surveying instrument used should be of gyroscopic character, and the records made'photographically.

Other objects of the invention will be apparent 15 from the following description read in conjunction with the accompanying drawing in which:

Fig. 1 is a sectional view showing the assembly v oi' thel drill stem, well ysurveying instrument and whipstock vprior to sett hg;

Fig. 2 is a plan viewl of the type of photographic record made by the surveying instrument; and

Fig. 3 is a sectional view showing the relation#- ship of various parts of the surveying instrument.

In carrying outI the improved method, it is 25 rst necessary to make a complete directional survey of the bore hole. 'Ihis must be done by the use of some instrument which is not in itself affected by errors due to tortuosity, namely,

an instnnnent which contains within itself an 30- element for correctly indicating the azimuth. vIt may be pointed out that if the survey was made by drill stem orientation, the tortuosity errors would be cumulative. In accordance with the present invention, however, the only tor- .35 tuosity errors are those which may arise in the setting of the whipstock itself. 'I'he errors are thereby minimized particularly made by drill -stem orientation are large errors due to inaccuracies /various sections 9i the stem.

Both gyroscpic and magnetic instruments vwould satisfy the requirement for avoidance of errors due to tortuosity, but the only 'type of instrument which is fully ings by mineral deposits netic bodies-artificially. present in the bore hole. An accurate survey with no errors due to torlikely to have since surveys.

in aligning the 4o stock isv to be understood to be conventional.

since the whipstock may be of any Vwell known type involving, for example, an automatic arl rangement designed to engage and hold the bot- 'tom of the whipstock at the position of a Joint in a casing. vThe whipstock may also be of the type designed to be secured in place by cementing. The type of whipstock here illustrated, provided with a chiselshaped lower end, would be held in place by being forced into the soil at .the bottom of the bore hole.

The whipstock is secured by means of a soft metal rivet or pin 6 to an extension of a setting tool I0, which is coupled by mans of a sub l2 to the outer casing .i4 of a battery container, which is indicated as lled with a suitable number of batteries I6. This casing is in turn connected by a coupling i8 to theouter casing 20 of a surveying instrument of the type described in the above mentioned Williston and Nichols patent. This surveying instrument comprises three parts indicated .at 22, including a gyroscope, a

. timepiece and a box level, which are arranged to be simultaneously photographed by the use of a motion picture camera making successive exposures at suitably timed intervals.

Above the surveying instrument there is provided a coupling 24 provided with mud passages 26, to which coupling there is secured the lowerf" most section 28 of the drill stem on which the apparatus is lowered.

The details ofthe well surveying instrument corresponding to that of the Williston and Nichols patent are indicated in Fig. 3, and also on the record illustrated in Fig. 2. The vertical gimbal ring of a gyroscope carries a pointer 3|! which moves adjacent a scale 32. Current is led into the gyroscope by means of a lead 34 which vextends in a plane above that of movement of the pointer 30. Located adjacent 'the scale 22 is. a watch 3B which serves to indicate permanently on the records the times at which exposures are made. A `camera 3i is located above the gyroscope and serves not only to take pictures of the gyroscopev pointer and the adjacent pieces of apparatus, but also makes simultaneous exposures of a box level, indicated -at 3l, provided with concentric lines on its transparent cover, in contact with-which there moves a bubble 4lv serving to indicate the inclination of the device. Lamps 33 are provided to'furnish illumination of the parts for the production of exposures. Movements of the nlm vof the camera and the illumination are controlled by means of .a mecha-- nism indicated at 35, which serves to prevent the formation or an excessive number of exposures inl the relatively'I long intervali'nvolved in lowering and locating the whipstock. l

'111e surveying instrument is oriented into a known position relative to the whipstock so that, from the readings obtained in the instrument, the final position of the whipstock will be accurately distances along the path of a bore hole. Such inknown. Either a line 42 inscribed on the cover glass ofthe level 38, or the electrical lead 34 may be used as the zero of reference of the scale 32, or the scale itself may be suitably marked with a zero indication. Whatever this indication may be, it is brought into position bearing a definite relationship to the inclined face of the whipstock. It will be understood, of course, that the box level occupies a' fixed angular position in the casing relative to the gyroscope scale. The mark 42 inscribed on the cover of the level is desirable since, while the lead 34 is generally visible, it is to some extent out of focus, being disposed in a plane above that in which the pointer 30 moves.

The box level forms an integral part of the surveying instrument to which reference has been made. It will be obvious, however, that the indications of the box level are not necessary to the carrying out of the method herein described. It is, however, convenient to have this check' upon the inclination of the bore hole at the position where the whipstock is set.

The various sections ofthe drill stem are lined up relative to each other and the surveying instrument and whipstock by the usual process involving the alignment of successive fourbles relative to each other. 'Ihis may be eiected by the well known procedure of attaching targets to the bottoms and tops of the fourbles and sighting these targets, successively moving them upwardly in steps as the drill stem is lowered by iourble' lengths.- The drill stem may be turned to secure proper alignment or, alternatively, the misalignment may be noted and correction made. The process may b e carried out either by sighting targets attached to the fourble lengths, or by clamping to the fourble lengths telescopes or other sighting instruments directed toward iixed distant objects. This method of orientation of the various lengths to secure a known alignment throughout the entire length of the drill .stern is well known and the speciiic steps involved need not be described'herein in'detail. It is the same vprocedure as is frequently followed in making well surveys.

As the whipstock is brought to its position, the surveying instrument continues to operate to record its actual position; the drill stem being turned to'bring the whipstock into the calculated position. The timepiece will indicate those exposures which are made when the whipstock is finally in position by merely noting thetime at which such position is attainedon a watch at .the surface synchronized with 'that within the in strument.

. After the desired position of the whipstock is reached it is set and held in place by that method which is suitable for the particular whipstock being used. In the present instance, for example, the chisel-shaped lower end of the whipstock is forced'mto the son at the bottom of the bore hole or into cement if thelower portion of the,

bore hole has been partially lled therewith. If another type of whipstock is used, securing of it in position is accomplished in the corresponding suitable fashion. The securing of the whipstock in place may initially be temporary, more permanent securing ,thereof being obtained by cementowing permanent or temporary fixation oi the whipstock, the drill. stem is pressed downor'. pin i, leaving the whipstock-free of the lower end oi the drill stem, which'is then withdrawn,

wardiy witnsumcient force to meer off the rivet v ing claims.

Y correction tice of the invention records of the surveying instrument may thenl be examined to determine whether the whipstock actually has the proper position. Following the check of this position, drilling may be resumed in any of scribed fully in the article referred to above.

Various details of manipulation need not be described here since they are well known and are brought out, for example, in said article. If the deflection is to take place not in the bottom of a bore hole but at some intermediate position for the purpose, for example, of forming branches, then the various procedures specied in the article may be used to secure the positioning oi' the whipstock at -the proper location. For example, the bore hole may be plugged back to a given position by the lowering of old drill stem piping or the use of cement.

The advantages oi' this method are primarily in that it makes possible the checking of the setting of a whipstock in a convenient and rapid fashion. The direction of the setting oi! the whipstock is photographically recorded in one round trip of the drill stem. A considerable'expense is saved by avoiding a second trip into the hole with a surveying instrument for the purpose of checking the orientation of the whipstock. 'I'his check is of great value since it the whipstock setting should happen to be improper for any reason may be made by the use of a double whipstock as lin the process described in the publication mentioned above.

It will be clear that variations inthe pracmay be made without departing from its scope; as defined by the follow- What I claim and desire to protect by Letters Patent is:

v 1. 'I'he method oi' orienting a whipstock within a b ore hole including lowering the whipstock into the bore hole, there being lowered with the whipstock an instrument arranged to indicate photograpmcany th azimuthal position or the wmpstock, the intrument being adjacent the whipstock and attached thereto; causing the whipstock to the usual `fashions, for example, as deassume a predetermined position; photographically recording the azimuthal positionl oi.' the whipstock in said predetermined position `by means'ot said instrument; fixing the whipstock in such position; and then withdrawing the instrument.

2. The method of orienting a whipstock within a bore hole includinglowering the whipstock into the bore hole by means of a sectional drill stem, the sections of which are' lined up relatively to each other, there being lowered with the whipstock an instrument arranged to 'indicate photographically the azimuthal position of the whipstock, the instrument being adjacent the whipstock and attached thereto;`turning the upper end oi' the drill stem to thereby bring the whipstock into a predetermined position; photographicallyv recording the azimuthal position of the whipstock in said predetermined position by means of said instrument; xing the whipstock in such position; and then withdrawing the instrument.

3. The method of orienting a whipstock within a bore hole including `lowering A the whipstock into the bore hole, there being lowered with the whipstock an instrument arranged to. record the azimuthal position of the whipstock, the instrument being adjacent the whipstock and attached thereto; causing the whipstock to assume a predetermined position; recording the azimuthal position of the whipstock in said predetermined position by means of said instrument; xing the whipstock in such position; and then withdrawing the instrument.

4. The method of orienting a whipstock within a bore-hole including lowering the whipstock into the bore-hole by means of a sectional drill stem; photographically recording the azimuthal position of the whipstock in its lowered position while it is secured to the drill stem by means of an instrument located adjacent the whipstock and bearing a determinable relationship thereto; and eieoting fixation of the whipstock in desired position and withdrawal of the instrument.

I SAMUEL H. WILLISTON. 

